German Patent DE 10 2007 028 799 A1 discusses an impedance-controlled coplanar waveguide system for distributing high-frequency signals. It proposes to dispose a coplanar waveguide between two circuit carriers, each of which is provided with electroconductive ground conductors.
Systems for distributing high-frequency signals are utilized in numerous fields of application. Thus, for example, many devices in the consumer-electronics sector, like cell phones, for instance, include an antenna system that is connected via suitable signal lines to a high-frequency unit for processing and generating high-frequency signals. Moreover, radar sensors, as used in modern motor vehicles, for example, likewise require a high-frequency distribution network which connects the antennas with the components for generating and processing signals. In that case, various forms of the suitable high-frequency lines may be provided for conducting and distributing the high-frequency signals.
For example, microstrip line waveguides (MSW) are familiar, where a stripline is disposed above a ground plane. For further shielding, the stripline may likewise be shielded laterally with additional ground leads. Such forms are known, for example, under the term Grounded Coplanar Waveguide (GCPW). In addition, what are referred to as Buried Grounded Coplanar Waveguides (BGCPW) are also familiar, where a stripline may be shielded above and below with the aid of ground leads. In particular, for example, the stripline may be disposed between two substrates like, e.g., printed-circuit-board substrates, the sides of the substrate facing away from the stripline in each case being provided with ground planes. The two ground planes may be connected to each other by vias, for example. In this case, the transition between different high-frequency lines represents a particular challenge.